Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

mcs/tests/gtest-linq-17.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+//
+// Tests whether group i by i is optimized
+//
+class TestGroupBy
+{
+	public static int Main ()
+	{
+		int[] int_array = new int [] { 0, 1, 2, 3, 4 };
+		
+		var e = from i in int_array group i by i;
+
+		int c = 0;
+		foreach (var ig in e) {
+			Console.WriteLine (ig.Key);
+			if (ig.Key != c++)
+				return c;
+		}
+		
+		Console.WriteLine ("OK");
+		return 0;
+	}
+}